A model experiment of dynamic loads on a draft tube pier
2008 (English)In: Hydro technology and the evironment for the new century: 24th IAHR Symposium on Hydraulic Machinery and Systems, October 27 - 31, 2008, Foz do Iguassu, Brazil, Foz do Iguassu, 2008Conference paper (Refereed)
Cracks on the pier of large draft tubes have occurred causing stand-still and repair of two large twin stations Porjus G11 and G12. In order to understand the mechanism behind the formation of the cracks, a research programme was initiated at Vattenfall. Measurements were performed on a prototype as well structural analysis (FEM). In order to corroborate some findings, get detailed information of the load on the pier and identify critical operating conditions, model tests were performed at the Hydraulic Machinery Laboratory of Vattenfall Research and Development, Älvkarleby, Sweden. An adjustable draft tube pier with several pressure holes was used to estimate the load acting on the pier. The tests did not indicate any operating point that would cause direct braking, but possible fatigue problems. At part load the pressure was considerably higher on one side of the pier. The pressure difference decreases with increased flow, and change high-pressure side at full load. Efficiency measurements and visualization did not show any impact of the angle bars installed in the year 2000 to strength the structure.
Place, publisher, year, edition, pages
Foz do Iguassu, 2008.
Research subject Fluid Mechanics
IdentifiersURN: urn:nbn:se:ltu:diva-27808Local ID: 15c900d0-b011-11dd-b677-000ea68e967bISBN: 978-85-60858-13-1 (PDF)OAI: oai:DiVA.org:ltu-27808DiVA: diva2:1000999
IAHR Symposium on Hydraulic Machinery and Systems : 27/10/2008 - 31/10/2008
Godkänd; 2008; Bibliografisk uppgift: 1 CD-ROM; 20081111 (ysko)2016-09-302016-09-30Bibliographically approved